This invention is related in general to the field of telecommunications equipment. More particularly, the invention is related to signal transfer point local number portability database audit system and method.
Local number portability (LNP) is a relatively recent development in the telephone industry that allows a telephone service subscriber to change the telephone company or carrier providing the service without having to change telephone numbers. Numbering plan splits in growing metropolitan areas to accommodate more subscriber telephone numbers also requires the local number portability service to properly route calls. To enable local number portability, centralized regional entities called the number portability administration center (NPAC) have been established to store and update the location and associated data on the ported telephone numbers residing in the telecommunications switching network. In addition, each service provider is required to provide a local service management system (LSMS) that will accept from NPAC the data related to telephone numbers and associated LNP data and then propagate them to signal transfer points (STPs) serviced by each service provider.
Between NPAC and SMS, the NPAC SMS Interoperability Interface Specification document prepared for the North American Number Council (NANC) contains the information model for the NPAC and SMS mechanized interfaces Between SMS and STP, typically CMIP/CMISE protocol is used, where CMIP/CMISE messages containing LNP data are exchanged between a software process called object manager running in SMS and a software process called object agent running in STP.
Typically, the signal transfer points are configured as mated pairs to operate in a load-sharing manner and to provide redundancy. Therefore, the local number portability databases maintained by mated pairs should contain identical data.
Due to a number of possible failures, the data in a local number portability database maintained by one signal transfer point may not match the data at its mate. Failures which may cause a data mismatch includes link failure between the local service management system and one of the signal transfer point nodes, hardware or software failure at one of the signal transfer point nodes, power failure at one of the signal transfer point nodes, or software/hardware maintenance, diagnosis, or upgrade during local number portability data update. Further, data mismatch may be caused by extended delays in data update request between the local service management system and one of the signal transfer points.
When data update requests are unsuccessful due to signal transfer point failure, maintenance, or extended network delays, some local service management system may have the capability to hold off or buffer update requests for approximately 15 minutes which, at a maximum allowable of 25 updates per second, may be a maximum of 22,500 updates. Most often, the failed signal transfer point is not able to recover within 15 minutes from failure or maintenance procedures. The problem is also intensified due to the size of a local number portability database, which typically has millions of entries.
Currently, there is no detection method to determine whether a mismatch condition in the data of the mated pairs exists. As a result, errors may occur when erroneous data is used to route calls to ported telephone numbers. Due to the nature of load sharing between mated STP pairs, the errors seem intermittent to callers, as one STP contains the new correct data and the other contains the old erroneous data.
Accordingly, there is a need for a system and method to detect data mismatch in the local number portability databases of mated signal transfer point pairs.
In one aspect of the invention, a method of auditing a first local number portability database associated with a first signal transfer point includes sending, by a first audit manager, a request to the first signal transfer point, the request specifying at least one ported telephone number. A first audit agent receives the request at the first signal transfer point, looks up the specified at least one ported telephone number in the first local number portability database, and obtains at least one corresponding local routing number. The first audit agent then sends the at least one corresponding local routing number to the first audit manager. The audit manager then compares the received at least one corresponding local routing number to data local to the first audit manager. The audit manager then reports the result of the comparison.
In another aspect of the invention, an automated method of determining data discrepancy in first and second mirrored databases is provided. The method includes sending, by a first audit manager, a request to access specific entries in the first database. A first audit agent associated with the first database then receives the request, looks up the specified entries in the first database, and obtains data corresponding thereto. The first audit agent sends the data to the first audit manager. The audit manager then compares the received data to data previously-obtained by the first audit manager, and reports the result of the comparison.
In yet another aspect of the invention, a signal transfer point local number portability audit system includes an audit manager operable to compose and send an audit request message to an audit agent associated with a first local number portability database. The audit request message specifies at least one ported telephone number. The audit agent is operable to receive the audit request message, look up the specified at least one ported telephone number in the first local number portability database, and composing and send an audit response message to the audit manager. The audit response message includes at least one local routing number corresponding to the specified at least one ported telephone number. The audit manager is operable to receive the audit response message, and compare the received at least one local routing number with at least one local routing number accessed from a second local number portability database. The audit manager then generates a report on the result of the comparison.